From 002cdb95dc398919bd37d3228c677a22c5ca1498 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Tue, 18 Jun 2019 17:17:13 -0700 Subject: [PATCH] Input: gpio_keys - use struct_size() in devm_kzalloc() One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct gpio_keys_drvdata { ... struct gpio_button_data data[0]; }; size = sizeof(struct gpio_keys_drvdata) + count * sizeof(struct gpio_button_data); instance = devm_kzalloc(dev, size, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = devm_kzalloc(dev, struct_size(instance, data, count), GFP_KERNEL); Notice that, in this case, variable size is not necessary, hence it is removed. This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva Signed-off-by: Dmitry Torokhov --- drivers/input/keyboard/gpio_keys.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c index 6cd199e8a370..c186c2552b04 100644 --- a/drivers/input/keyboard/gpio_keys.c +++ b/drivers/input/keyboard/gpio_keys.c @@ -774,7 +774,6 @@ static int gpio_keys_probe(struct platform_device *pdev) struct fwnode_handle *child = NULL; struct gpio_keys_drvdata *ddata; struct input_dev *input; - size_t size; int i, error; int wakeup = 0; @@ -784,9 +783,8 @@ static int gpio_keys_probe(struct platform_device *pdev) return PTR_ERR(pdata); } - size = sizeof(struct gpio_keys_drvdata) + - pdata->nbuttons * sizeof(struct gpio_button_data); - ddata = devm_kzalloc(dev, size, GFP_KERNEL); + ddata = devm_kzalloc(dev, struct_size(ddata, data, pdata->nbuttons), + GFP_KERNEL); if (!ddata) { dev_err(dev, "failed to allocate state\n"); return -ENOMEM;